Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J45/00—Ion-exchange in which a complex or a chelate is formed; Use of material as complex or chelate forming ion-exchangers; Treatment of material for improving the complex or chelate forming ion-exchange properties
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
  • C01G3/00—Compounds of copper
  • C01G3/003—Preparation involving a liquid-liquid extraction, an adsorption or an ion-exchange
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
  • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
  • C22B3/42—Treatment or purification of solutions, e.g. obtained by leaching by ion-exchange extraction
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/20—Recycling

Definitions

• the invention relates to a method of separating heavy metals from complex-forming substances of aminocarboxylic acid type, or salts thereof in aqueous solution, as well as a method of removing heavy metals from the solutions containing said complex-forming substances.
• Solutions containing heavy metals in complex form and substancs of aminocarboxylic acid type, or salts thereof, are used and occur in metal finishing processes, galvanotechniques, preferably in the electroless copper coating process, further in hydrometallurgy and in decontaminating solutions in nuclear power stations.
• complex-forming substances there are used for this purpose nitrilotriacetic acid, hydroxyethylenediaminotriacetic acid (HEDTA) and ethylenediaminotetracetic acid (EDTA), or sodium salts thereof.
• HEDTA hydroxyethylenediaminotriacetic acid
• EDTA ethylenediaminotetracetic acid
• a common disadvantage of all of the aforementioned processes consists in that residual heavy metal concentrations in treated water do not always meet the water system requirements; further, in a relatively low reaction rate of precipitation, with a poor sedimentation of the precipitate, the necessity of using a relatively considerable excess of chemicals and precipitants (which remain in the treated water), results in a hygienic defectiveness in case of using sulphides and derivatives thereof; and finally, in that in all of the cases there arise large amounts of sludge, making the recovery of metals from them very difficult.
• an anion exchanger having polyethyleneimine active groups is contacted, most preferably dynamically in a column, with a solution containing heavy metals in complex form and complex-forming substances. Recaptured heavy metals are then displaced out of the ion exchanger, which is already in the form of free non-complex cations, by an acid solution which is allowed to pass through the column containing the chelating ion exchanger.
• An advantage of the process according to the invention consists in that the polyethyleneimine active groups of the ion exchanger exhibit as high an affinity to heavy metals as being capable of splitting a bond between the heavy metal and the chelate substance in a solution, so that free heavy metal cations get into the ion exchanger phase where they are taken up by bonds to the imine groups of the ion exchanger.
• a positive charge of such very firmly bound heavy metal cations has to be compensated for--in order to keep the condition of electronneutrality--by a negative charge of anions which are present in the solution.
• These anions are bound to the ion exchanger by electrostatic attraction forces and, consequently, they are freely exchangable for any other anions which are present in the solution. This is why in the presence of EDTA in the solutions, the complex forming substance is electrostatically taken up by the resin in a molar ratio of 1:2 (i.e. EDTA:heavy metal cations bound by the coordinating bond).
• a selective displacement of electrostatically bound EDTA anions can be effected, for instance, by MgSO 4 solution while heavy metals remain firmly bound by the ion exchanger. If the sorption takes place at a relatively high pH value, or without adding Mg 2+ or Ca 2+ to the treated solution, then the recaptured EDTA amount is low and it is unnecessary to carry out the selective displacement of the electrostatically bound EDTA anion.
• the method of the invention makes it possible to separate heavy metals from chelating substances, and to recover heavy metals in such concentrations that facilitate the reuse thereof so that in waste water treatment the arising of any toxic waste is prevented.
• a quantitative displacement of recaptured copper was effected by 120 ml of 1.5M H 2 SO 4 at the flow rate of 60 ml per hour.
• the regeneration eluate was then alkalized to a pH value of from 10 to 11, and after sedimenting a precipitated copper hydroxide, the 0.8 mg/liter copper concentration in the supernatant solution was determined.
• the method provided by the present invention is applicable in the treatment of waste water left after currentless copper coating processes in the electronic industry, further for separating heavy metals in complex form from solutions left after ore leaching in the metallurgical industry, and for purifying decontamination solutions in nuclear power stations.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Geology (AREA)
• Manufacturing & Machinery (AREA)
• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Inorganic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Treatment Of Water By Ion Exchange (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Removal Of Specific Substances (AREA)

Applications Claiming Priority (2)

Publications (1)

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Cited By (10)

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Citations (10)

• 1984
  • 1984-06-01 CS CS844133A patent/CS245861B1/cs unknown
• 1985
  • 1985-05-14 DE DE19853517400 patent/DE3517400A1/de not_active Withdrawn
  • 1985-05-28 JP JP60113316A patent/JPS60264325A/ja active Pending
  • 1985-05-30 US US06/739,127 patent/US4664810A/en not_active Expired - Fee Related

Patent Citations (10)

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